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From: Manikanta Maddireddy <mmaddireddy@nvidia.com>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: <bhelgaas@google.com>, <robh+dt@kernel.org>,
	<mark.rutland@arm.com>, <jonathanh@nvidia.com>,
	<lorenzo.pieralisi@arm.com>, <vidyas@nvidia.com>,
	<linux-tegra@vger.kernel.org>, <linux-pci@vger.kernel.org>,
	<devicetree@vger.kernel.org>
Subject: Re: [PATCH 14/30] PCI: tegra: Set target speed as Gen1 before link up
Date: Mon, 15 Apr 2019 20:42:37 +0530
Message-ID: <75493937-fd77-024b-0e07-62ecc009c917@nvidia.com> (raw)
In-Reply-To: <20190415115218.GP29254@ulmo>



On 15-Apr-19 5:22 PM, Thierry Reding wrote:
> On Thu, Apr 11, 2019 at 10:33:39PM +0530, Manikanta Maddireddy wrote:
>> Some of the legacy PCIe endpoints doesn't enumerate if root port advertises
>> both Gen-1 and Gen-2 speeds. Hence, the strategy followed here is to
>> initially advertise only Gen-1 and after link is up, retrain link to Gen-2
>> speed.
>>
>> Following two cards display this behaviour,
>>   - Fusion HDTV 5 Express card
>>   - IOGear SIL - PCIE - SATA card
>>
>> Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
>> ---
>>  drivers/pci/controller/pci-tegra.c | 11 +++++++++++
>>  1 file changed, 11 insertions(+)
>>
>> diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c
>> index 7dc728cc5f51..7e24eac12668 100644
>> --- a/drivers/pci/controller/pci-tegra.c
>> +++ b/drivers/pci/controller/pci-tegra.c
>> @@ -670,6 +670,17 @@ static void tegra_pcie_apply_sw_fixup(struct tegra_pcie_port *port)
>>  		value |= soc->update_fc_val;
>>  		writel(value, port->base + RP_VEND_XP);
>>  	}
>> +
>> +	/*
>> +	 * PCIe link doesn't come up with few legacy PCIe endpoints
>> +	 * if root port advertises both Gen-1 and Gen-2 speeds.
>> +	 * Hence, the strategy followed here is to initially advertise
>> +	 * only Gen-1 and after link is up, retrain link to Gen-2 speed
>> +	 */
>> +	value = readl(port->base + RP_LINK_CONTROL_STATUS_2);
>> +	value &= ~PCI_EXP_LNKSTA_CLS;
>> +	value |= PCI_EXP_LNKSTA_CLS_2_5GB;
>> +	writel(value, port->base + RP_LINK_CONTROL_STATUS_2);
>>  }
>>  
>>  static void tegra_pcie_port_enable(struct tegra_pcie_port *port)
> This looks like it's related to the earlier patch that adds support for
> retraining the link at Gen-2. As such, I think the two patches should be
> moved closer together to make that more obvious.
>
> Also, perhaps even the order needs to be changed. For example, if the
> earlier patch enables advertisement of Gen-2, then there will be a
> period of 10 or so patches where the above devices wouldn't work. So if
> this fixes an error introduced by an earlier patch, it makes sense to
> resort the patches so that we first fix the potential error and then
> introduce the code that would cause the error to happen.
>
> Thierry
Both are independent patches. Even though HW init Target speed is Gen2, Tegra
PCIe gets the link up in Gen1 only because HW autonomous speed change feature
is not available. After link up in Gen1 SW has to retrain the link to Gen2, which is
done in 4/30. Current patch changes the HW init value of Target speed to Gen1,
to support the cards mentioned in commit message.

  reply index

Thread overview: 106+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-11 17:03 [PATCH 00/30] Enable Tegra PCIe root port features Manikanta Maddireddy
2019-04-11 17:03 ` [PATCH 01/30] soc/tegra: pmc: Export tegra_powergate_power_on() Manikanta Maddireddy
2019-04-11 17:03 ` [PATCH 02/30] PCI: tegra: Fix PCIe host power up sequence Manikanta Maddireddy
2019-04-15 11:01   ` Thierry Reding
2019-04-15 14:11     ` Manikanta Maddireddy
2019-04-15 14:30       ` Thierry Reding
2019-04-15 18:14         ` Manikanta Maddireddy
2019-04-11 17:03 ` [PATCH 03/30] PCI: tegra: Move REFCLK pad settings out of phy_power_on() Manikanta Maddireddy
2019-04-15 11:06   ` Thierry Reding
2019-04-15 14:20     ` Manikanta Maddireddy
2019-04-11 17:03 ` [PATCH 04/30] PCI: tegra: Add PCIe Gen2 link speed support Manikanta Maddireddy
2019-04-15 11:21   ` Thierry Reding
2019-04-15 14:47     ` Manikanta Maddireddy
2019-04-15 15:36       ` Thierry Reding
2019-04-15 15:53         ` Manikanta Maddireddy
2019-04-11 17:03 ` [PATCH 05/30] PCI: tegra: Advertise PCIe Advanced Error Reporting (AER) capability Manikanta Maddireddy
2019-04-15 11:23   ` Thierry Reding
2019-04-15 14:49     ` Manikanta Maddireddy
2019-04-11 17:03 ` [PATCH 06/30] PCI: tegra: Program UPHY electrical settings for Tegra210 Manikanta Maddireddy
2019-04-15 11:29   ` Thierry Reding
2019-04-15 14:55     ` Manikanta Maddireddy
2019-04-15 15:38       ` Thierry Reding
2019-04-11 17:03 ` [PATCH 07/30] PCI: tegra: Enable opportunistic update FC and ACK Manikanta Maddireddy
2019-04-15 11:30   ` Thierry Reding
2019-04-11 17:03 ` [PATCH 08/30] PCI: tegra: Disable AFI dynamic clock gating Manikanta Maddireddy
2019-04-15 11:32   ` Thierry Reding
2019-04-11 17:03 ` [PATCH 09/30] PCI: tegra: Process pending DLL transactions before entering L1 or L2 Manikanta Maddireddy
2019-04-15 11:33   ` Thierry Reding
2019-04-11 17:03 ` [PATCH 10/30] PCI: tegra: Enable PCIe xclk clock clamping Manikanta Maddireddy
2019-04-15 11:37   ` Thierry Reding
2019-04-15 14:58     ` Manikanta Maddireddy
2019-04-11 17:03 ` [PATCH 11/30] PCI: tegra: Increase the deskew retry time Manikanta Maddireddy
2019-04-15 11:39   ` Thierry Reding
2019-04-15 14:58     ` Manikanta Maddireddy
2019-04-11 17:03 ` [PATCH 12/30] PCI: tegra: Add SW fixup for RAW violations Manikanta Maddireddy
2019-04-11 20:01   ` Bjorn Helgaas
2019-04-12  5:59     ` Manikanta Maddireddy
2019-04-15 11:41       ` Thierry Reding
2019-04-15 11:45   ` Thierry Reding
2019-04-15 15:02     ` Manikanta Maddireddy
2019-04-11 17:03 ` [PATCH 13/30] PCI: tegra: Update flow control threshold in Tegra210 Manikanta Maddireddy
2019-04-15 11:47   ` Thierry Reding
2019-04-15 15:05     ` Manikanta Maddireddy
2019-04-23  9:27       ` Manikanta Maddireddy
2019-04-11 17:03 ` [PATCH 14/30] PCI: tegra: Set target speed as Gen1 before link up Manikanta Maddireddy
2019-04-11 20:04   ` Bjorn Helgaas
2019-04-12  6:44     ` Manikanta Maddireddy
2019-04-12 14:35       ` Bjorn Helgaas
2019-04-15 10:43         ` Manikanta Maddireddy
2019-04-15 11:52   ` Thierry Reding
2019-04-15 15:12     ` Manikanta Maddireddy [this message]
2019-04-11 17:03 ` [PATCH 15/30] PCI: tegra: Fix PLLE powerdown issue due to CLKREQ# signal Manikanta Maddireddy
2019-04-15 13:17   ` Thierry Reding
2019-04-15 15:14     ` Manikanta Maddireddy
2019-04-11 17:03 ` [PATCH 16/30] PCI: tegra: Program AFI_CACHE* registers only for Tegra20 Manikanta Maddireddy
2019-04-15 13:20   ` Thierry Reding
2019-04-16 10:47     ` Manikanta Maddireddy
2019-04-16 16:11       ` Thierry Reding
2019-04-11 17:03 ` [PATCH 17/30] PCI: tegra: Use switch statements in tegra_pcie_isr() Manikanta Maddireddy
2019-04-15 13:25   ` Thierry Reding
2019-04-15 15:25     ` Manikanta Maddireddy
2019-04-11 17:03 ` [PATCH 18/30] PCI: tegra: Change PRSNT_SENSE irq log to debug Manikanta Maddireddy
2019-04-11 17:03 ` [PATCH 19/30] PCI: tegra: Use legacy irq for port service drivers Manikanta Maddireddy
2019-04-15 13:35   ` Thierry Reding
2019-04-11 17:03 ` [PATCH 20/30] PCI: tegra: Add AFI_PEX2_CTRL reg offset as part of soc struct Manikanta Maddireddy
2019-04-15 13:31   ` Thierry Reding
2019-04-11 17:03 ` [PATCH 21/30] PCI: tegra: Add "pci" type check before parsing child device tree node Manikanta Maddireddy
2019-04-15 13:37   ` Thierry Reding
2019-04-15 15:30     ` Manikanta Maddireddy
2019-04-15 15:42       ` Thierry Reding
2019-04-11 17:03 ` [PATCH 22/30] PCI: tegra: Access endpoint config only if PCIe link is up Manikanta Maddireddy
2019-04-11 20:15   ` Bjorn Helgaas
2019-04-12  7:00     ` Manikanta Maddireddy
2019-04-12 14:50       ` Bjorn Helgaas
2019-04-15 11:36         ` Manikanta Maddireddy
2019-04-15 13:45           ` Thierry Reding
2019-04-15 13:52             ` Thierry Reding
2019-04-15 14:04           ` Bjorn Helgaas
2019-04-15 15:43             ` Manikanta Maddireddy
2019-04-23 20:24               ` Bjorn Helgaas
2019-04-11 17:03 ` [PATCH 23/30] dt-bindings: pci: tegra: Document PCIe DPD pinctrl optional prop Manikanta Maddireddy
2019-04-15 14:07   ` Thierry Reding
2019-04-15 15:48     ` Manikanta Maddireddy
2019-04-11 17:03 ` [PATCH 24/30] arm64: tegra: Add PEX DPD states as pinctrl properties Manikanta Maddireddy
2019-04-11 17:03 ` [PATCH 25/30] PCI: tegra: Put PEX CLK & BIAS pads in DPD mode Manikanta Maddireddy
2019-04-15 14:11   ` Thierry Reding
2019-04-11 17:03 ` [PATCH 26/30] dt-bindings: pci: tegra: Document nvidia,plat-gpios optional prop Manikanta Maddireddy
2019-04-11 20:18   ` Bjorn Helgaas
2019-04-12  7:01     ` Manikanta Maddireddy
2019-04-15 14:16   ` Thierry Reding
2019-04-15 17:58     ` Manikanta Maddireddy
2019-04-16 15:34       ` Thierry Reding
2019-04-17 11:22         ` Manikanta Maddireddy
2019-04-17 15:19           ` Thierry Reding
2019-04-17 18:26             ` Manikanta Maddireddy
2019-04-11 17:03 ` [PATCH 27/30] PCI: tegra: Add support to configure platform GPIOs Manikanta Maddireddy
2019-04-11 17:03 ` [PATCH 28/30] dt-bindings: pci: tegra: Document nvidia,rst-gpio optional prop Manikanta Maddireddy
2019-04-15 14:20   ` Thierry Reding
2019-04-15 18:01     ` Manikanta Maddireddy
2019-04-29 18:33     ` Rob Herring
2019-04-11 17:03 ` [PATCH 29/30] PCI: tegra: Add support for GPIO based PCIe reset Manikanta Maddireddy
2019-04-15 14:20   ` Thierry Reding
2019-04-15 18:03     ` Manikanta Maddireddy
2019-04-11 17:03 ` [PATCH 30/30] PCI: tegra: Change link retry log level to INFO Manikanta Maddireddy
2019-04-15 14:23   ` Thierry Reding
2019-04-15 18:05     ` Manikanta Maddireddy

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